1. Field of the Invention
The present invention relates generally to vehicle navigation apparatuses and, more particularly, to a vehicle navigation apparatus displaying enhanced information regarding geographic entities, such as the names, sizes, and boundaries of municipalities, counties, and states.
2. Description of the Related Art
A vehicle navigation apparatus of a well-known type performs vehicle travel guidance, enabling a driver to easily drive the vehicle to a desired destination. The navigation apparatus detects the position of the vehicle, reads out map data pertaining to an area in which the vehicle is positioned from, e.g., a CD-ROM (compact disk read-only memory), and displays a map image on a display screen while superimposing a mark representing the position of the vehicle (user""s vehicle position mark) on a predetermined portion of the map image. As the present position of the vehicle changes with movement of the vehicle, either the vehicle position mark in the image is moved or the map is scrolled while the vehicle position mark is fixed at a predetermined position, for instance at the center of the image, thereby enabling the driver to recognize the map information of the area at the vehicle position at a glance. This independent movement of the vehicle mark and the map is typically achieved by composing the display from a plurality of layers overlaid on each other, with one layer displaying the vehicle mark, another layer displaying the map, etc. Displays are available at a plurality of scale, or zoom, levels, e.g. large-scale displays for urban areas with comparatively many roads and small-scale displays for rural areas with comparatively few roads. A typical large-scale display might show approximately {fraction (1/10)} or ⅝ of one square mile, while a typical small-scale display might show 9,000 or 100,000 square miles. Between these two, a typical middle-scale map might show 10 or 160 square miles.
A first problem with currently-available vehicle navigation apparatuses is that they do not display names or boundaries of municipalities, counties, or states, which can lead to a driver""s becoming disoriented by not knowing the name of the current or adjacent municipality, county, or state; or, if they do display names of municipalities, counties, or states, these names are displayed in small fonts over the street names, which can lead to crowding of the display and resultant confusion of the user.
A second problem with currently-available navigation apparatuses is that they display all municipalities as uniformly-sized, uniformly-shaped dots when in small-scale or middle-scale mode. This does not tell the driver whether a given municipality is a large metropolitan area or a small town, and does not tell the driver the approximate shape of the municipality""s boundaries or road network.
A third problem with currently-available navigation apparatuses is that they do not display point-of-interest (POI) icons in small-scale displays to indicate availability of services that are useful to drivers in rural areas, such as gas stations, restaurants, and lodging.
A fourth problem with currently-available navigation apparatuses is that they do not display enough roads in rural areas when in small-scale mode. The apparatuses typically assign a xe2x80x9cpriority,xe2x80x9d or importance, to each road, and display only roads at or above a certain predetermined priority to avoid over-crowding a small-scale display. For instance, displaying an interstate highway is considered to be more useful to a driver than is displaying a two-lane county road, so the interstate highway is assigned a higher priority and is more likely to be displayed. This is important in urban areas that have a high density of roads. In small-scale displays of rural areas, though, where many of the roads are sparsely situated and of low priority, the apparatuses tend to display too few roads, because the low density of the existing roads is exacerbated by the roads"" priorities being below the predetermined level for display.
Therefore, it is a first object of the present invention to display names of municipalities, counties, and/or states, depending on scale; to do so in such a manner that state names can be easily distinguished from municipality and/or county names; and to do so in such a manner that municipality, county, and state names can be easily distinguished from street names.
It is a second object of the present invention to use different colors to display adjacent municipalities, counties, and states, depending on scale.
It is a third object of the present invention to use icons of varying sizes to represent municipalities on small-scale displays, the size of each icon being dependent on the size of the municipality it represents.
It is a fourth object of the present invention to use icons of varying shapes to represent municipalities on small-scale displays, the shape of each icon being dependent on the shape of the boundaries of the municipality it represents.
It is a fifth object of the present invention to use street network outlines to represent municipalities on small-scale displays, the shape of each street network outline being dependent on the shape of the street network of the municipality it represents.
It is a sixth object of the present invention to use fixed-size icons of one or more colors and/or design patterns to represent municipalities on small-scale displays, the colors and/or design patterns being dependent on the size and/or importance of the municipality it represents.
It is a seventh object of the present invention to display point-of-interest icons on small-scale displays of rural areas to indicate availability of services that are useful to drivers, such as gas stations, restaurants, and lodging.
It is an eighth object of the present invention to display roads of relatively lower priority on small-scale displays of rural areas, the adjustment of priorities being dependent on the density of the road network in the surrounding area.
It is a ninth object of the present invention to provide defaults for each of the displays described in the first eight objects, but also to provide means for user input to affect the display of each of the first eight objects.
According to the present invention, the first object is achieved by storing the names of geographic areas (e.g. municipalities, counties, states, ZIP code zones, telephone area codes, and the like) in a map database, and displaying the names of municipalities, counties, and/or states depending on display scale and display criteria. Preferably, state names are visually distinguishable from municipality and county names when displayed. A preferred method of making the displayed names visually distinct is displaying state names entirely in upper-case letters and displaying municipality and county names in mixed-case, i.e. upper-case mixed with lower-case, letters. A preferred method of distinguishing place names from street names is to display the place names in a layer, a size, a typeface, a style, and/or a color that are distinct from the street name display. Text orientation also helps distinguish place names from street names, as place names remain horizontal while street names follow angles of roads.
According to the present invention, the second object is achieved by storing information regarding the boundaries of geographic areas (e.g. municipalities, counties, states, ZIP Code zones, telephone area codes, and the like) in the map database; assigning colors to areas such that no adjacent geographic areas are assigned the same color; and displaying the colors for cities, counties, states, and/or other geographic areas on the portion of the display representing the particular geographic area, depending on display scale and display criteria.
According to the present invention, the third through fifth objects are achieved by storing the sizes of municipalities in the map database; storing a boundary shape for each municipality above a first predetermined size in the map database; storing the street network outline for each municipality above a second predetermined size in the map database; and displaying an icon representing the size, shape, and/or street network outline for each municipality depending on municipality size and display scale.
According to the present invention, the sixth object is achieved by identifying municipalities of applicable sizes and situations (relative importance within the region) in the map database; storing an icon for each applicable municipality; and displaying an icon representing the municipality, depending on the display scale, municipality size, and situation.
According to the present invention, the seventh object is achieved by identifying locales of applicable sizes and situations (relative importance within the region) in the map database; storing an icon for each type, and/or for all types combined, of predetermined services available within the locale; and displaying an icon representing the locale where a service or services are available, depending on the display scale and situation.
According to the present invention, the eighth object is achieved by evaluating the density of roads in an area, and adjusting the priority screening data to select lower-priority roads to be displayed on small-scale displays of rural areas.
According to the present invention, the ninth object is achieved by providing default displays for each of the first eight objects; providing a physical user input device or remote controller; and using input from the remote controller to override the default displays.